Burner safety control system and apparatus



Sept. l1, 1951 w. E. `EDELMAN Y BURNER SAFETY CONTROL SYSTEM AND APPARATUS 2 Sheets-Sheet 1 Filed Oct. 2, 1947 Gttorneg Sgpt. 1l, 1951 w. E. EDELMAN 2,567,807

I BURNER SAFETY CONTROL SYSTEM AND APPARATUS mled oct?. 2, 1947 2 sheets-sheet 2 IGNITEI? Snnentor WHL 72:5' f. EDE/ MHN @f7/$4 Gttorneg Patented Sept. 11, 1951 BURNER SAFETY CONTROL SYSTEM AND APPARATUS p Walter Edelman, Minneapolis, Minn., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation oi' Delaware Application October 2, 1947, Serial No. 777,407

This invention relates to a fuel burner control system and apparatus and, more particularly, to a system having a control station remote from the fuel burner.

One of the objects of the invention is to provide control apparatus whereby, for example, a householder may start operation of the heating system from a frequently occupied room remotely positioned from the heating plant.

Another object of the invention is to provide a'remote control apparatus of such simple operation that a home owner need not require the gas company or service man to come out and light the pilot in the fall and turn oi the system in the spring.

Another object of the invention is to provide fuel burner control apparatus which, when started manually, will automatically start and maintain the ow of fuel to a pilot burner, cause energization of an igniter, and then simultaneously deenergize the igniter upon the establishment of combustion at the pilot burner and complete a circuit to a main burner control system.

Another object of the inventionnis'to Provide a remote \control instrument which is able to signal to anoperator, such as a householder, that an undesirable operating condition exists in the controlled heating system.

Still another object of the invention is to provide a simple and inexpensive controller or control device that is adapted to cause ignition of a pilot burner either from a remote electrical control panel or manually at the control device.

A further object of the invention is to provide a controller or control device that is adapted to initiate and maintain a supply of fuel to a lburner and then automatically energize an igniter for said fuel. l

Still further objects of the invention will become apparent upon reading the following detailed description thereof in conjunction with the accompanying drawing wherein:

Figure l is an elevational view of the controller with its cover removed and a portion of its casing broken away;

Figure 2 is a cross sectional view of the controller taken along line 2-2 of Figure l;

Figure 3 is a cross sectional view of the conroller taken along line 3-3 of Figure 1; and

Figure 4 is a schematic view of the system and apparatus.

As seen in Figure 4 of the drawing, the control apparatus and system of this invention isadapted to be connected to most any conventional control apparatus for a main fuel burner. For example, the upper lead of the leads designated by the legend to main burner control could be connected to a room thermostat that is in turn connected to one terminal of a solenoid gas valve, while the other of said leads could be connected 9 Claims. (Cl. 158-28) to the other terminal of said solenoid valve control. f

The control device or controller, generally designated by the reference numeral I I, is shown in detail in Figures i to 3. It comprises a mounting plate I2 having an inlet I3 adapted to be connected to a source of fuel (not shown) and an outlet Il adapted to be connected to a pilot burner (not shown). The mounting plate has passages I5 and I5 which lead respectively, to and from a control means or pilot valve I1 mounted thereon and secured thereto as by means of screws I8. The mounting plate itself is adapted to be secured to any suitable support (not shown) adjacent the burner apparatus or the fuel supply lines leading thereto.

The control means, which in the preferred embodiment of the invention is a pilot valve I1, the details of which form no part of this invention, has a bifurcated actuating arm I 9 and a bifurcated strain release arm 20 secured to and in spaced relationship with said arm I9. The pilot valve is so designed that when the arm I9 is in its lowermost position, the valve is closed, and when the arm I9 is in its uppermost position, the pilot valve is opened.

Also mounted on the plate I2, by means of screws 2|, is a housing 22, open at one side and having an opening 23 .in the bottom thereof through which the pilot valve I1 extends upwardly into said housing. The housing also has a plurality of openings in the back or opposite side from the open side of the housing, which are adapted to receive the operating shaft of a manual controller and a plurality of terminal members to be described hereinafter. A cover member 24 is adapted to be secured to the housing 22 by means of screws 25 to close said open side.

A panel member 26, made of electrical insulating material, and a metallic frame member 21 are both secured to the back side of the housing 22 by means of screws 28, with the panel 26 positioned between the frame member 21 and the back side'of the housing. The frame member 21 is additionally secured to the panel member 26 by means of rivets 23. It is thus seen that the members 2E and 21 form a detachable mounting base for the control elements now to be described.

A power means or power actuator, preferably a heat motor, generally designated by the reference numeral 30, comprises a resistance heater 3l coiled around a bimetal member 32, an ac tuating arm 33 secured to the relatively free end of the bimetal member 32 by means of a rivet or any other suitable means, a bimetal compensating arm 3l, and a U-shaped bracket member 35, the legs of which are secured respectively to the left ends of the bimetal members 32 and 34 (as viewed in Figure 1)- by means of rivets or other suitable fastening means. The' heat motor 3l is pivotally secured to an arm 36 extending laterally from the frame member 21 by means of a spring hinge 31 riveted or otherwise secured at its ends to said arm and to the base of said U-shaped member 35. An adjustable abutment screw 33, which bears against the bottom oi bimetal member 34 in its lowermost position, is screw threaded into a split arm 38a extending laterally from the frame member 21. A tension spring 33, extending Ibetween an arm 40 on the frame member 21 and the outer free end of the arm 33, constantly urges the heat motor in a clockwise direction about pivot 31. An adjustable connecting screw 4| having spaced abutment shoulders 42 and 43 at its lower end, is screw threaded through the actuating arm 33 and extends through the bifurcated arms I9 and 20 of the pilot valve with said arms i3 and 20 positioned between said abutments. It is thus seen that the motor 31| is operatively connected to the pilot valve in such a manner that spring 33 normally holds said valve closed, but is adapted to move the valve to its open position, upon energization of the resistance heater 3| by warping the outer free end of the bimetal member 32 upwardly against the action of spring 39, which carries with it the connecting screw 4| and the valve arms 20 and I3. The bracket 35 is prevented from pivoting in a clockwise direction, upon energization of the heater 3|, due to the reactive force of the bimetal 34 against the adjustable abutment screw 38. The compensating bimetal is arranged so as to warp in the same direction as bimetal 32 so that any change that would normally take place in the position of the free end of the bimetal arm 32, due to changes in the ambient air temperature, will Ibe oil'set by the bimetal 34, a compensation well known in the art.

A switch having an adjustable contact 44, threaded through an arm 45 which is riveted or otherwise secured to panel 25 and having a nexible, normally open arm 45 secured to an arm 41 extending laterally from a terminal member 45, is positioned above said heat motor 30 so as to be actuated thereby. An insulation member 49, having reduced end portions 53 extending through apertures in members 45 and 33, causes the arm 45 to move to a closed position against contact 44 upon upward movement of the arm 33. The contact supporting arm 45 is electrically connected by means of connector wire 45a to a second power means or heat motor, generally designated by the reference numeral I The heat motor 5| has the same general construction as the heat motor 30 and is arranged with its longitudinal axis at right angles to the longitudinal axis of the heat motor 30. It comprises a resistance heater 52 surrounding a bimetal actuating arm 53 having a notch 54 spaced upwardly from the outer end thereof. The upper end of the bimetal arm 53 is riveted or otherwise secured to one end of a flexible pivot member 55 and one leg of a U-shaped bracket member 55. The other end of the flexible pivot member 55 is secured to a support arm 51 extending laterally from the frame mem-ber 21. The other leg of the U-shaped bracket member 55 is secured to a conventional bimetallic compensating arm 53 that is adapted to bear at its lower end against an adjustable abutment screw 59 threaded through an arm 50 extending from frame member 21. A compression spring 5| ex- 4 tends between the bimetal arm 53 and arm 32 extending laterally from frame member- 21. One end of the heater 52 is connected to the above mentioned connector 45a while the other end of the heater is electrically connected to terminal member 52h by means of a connector wire 52a.

The relationship of the lower end of arm 53 and the right hand end of arm 33, as viewed in Figure 1. is such that when the arm 33 is moved upwardly against the bias of spring 33 upon energization of the heater 3|, a portion of the arm 33 will slide through notch 54. This is due to the fact that when the shoulder formed by the notch 33a in the arm 33 is brought into alignment with the notch 54, the spring 5| is able to move the arm 53 toward the left. The spring 5| retains the arm 53 in this position and the arm 33 latched up and, consequently, the pilot valve I1 in its open position until the arm 53 is Warped toward the right upon energization of the heater 52 or by other means to be described hereinafter, Energization of heater 52 causes the arm 53 to move toward the right thereby moving the lower edge of the notch 54 out from under the shoulder formed on the arm 33, thus permitting spring 33 to lower the arm 33 and close the pilot valve.

A single pole, double throw switch, having a ilexible arm 53 carrying oppositely disposed contacts 54 and 55 near the lower end thereof, is pivotally connected to an arm 55 extending lateralli1 from a terminal member 51 riveted to the panel member 25. An adjustable contact member 53 screw threaded through an arm 53 extending laterally from a plate 13 riveted to the panel 25 is normally in engagement with contact member 55. A second adJustable contact member 1|, screw threaded through an arm 12 extending laterally from a terminal member 13 is secured to panel 26 and in spaced and opposed relationship with contact 54. The bias of the ilexible arm 53 is such that it normally tends to move contact 55 into engagement with adjustable contact 58. The arm 53 is moved in the other direction by means of an insulation bar 14 having reduced end portions 15 extending through apertures in exible arm 53 and bimetallic arm 530i the heat motor 5|. Arm 53, supporting contact member 53, is electrically connected-to the right hand end of heater 3| by means of lead wire 53a. It is thus seen that when the arm 33 is in its lowermost position, the heater 52 cannot become energized due to the fact that contact 44 is separated from contact 45, and when the arm 33 is in its uppermost position, the contact 44 is in engagement with contact arm l46 but contact 55 is out of engagement with contact 58 breaking the circuit to heater 3|. Therefore, it is apparent that only one of the heaters can be energized at one time.

Terminal member 15, as well as the other terminal members described before, is screw threaded to receive a lead clamping screw and is held against the inner side of the panel 25 by means of a split rivet 11 extending through an aperture in the panel 25 in alignment with one of the apertures in the back side of the housing 22, described above.. This terminal 15 is not connected to any of the elements of the controller but merely serves as a convenient means for electrically connecting other elements of the control apparatus, to be described hereinafter.

A safety pilot 18, shown schematically in Figure 4 oi the drawing and the details oi which form burner control circuit.

asomo? no part of this invention, comprises a contact arm 19 adapted to be moved by a conventional name sensing member into engagement with a cold contact C when no flame ispresent at the pilot burner, and into engagement with the "hot contact H. when flame is present atthe pilot burner. `The conventional means for actuating the contact arm 19 is preferably the well known thermocouple-relay combination. The hot terminal of the safety pilot is connected by a sultable lead to one end of a break in the main The "cold contact is connected through terminal 3|b to heater 3|, to one side each of an igniter transformer 83 and a signal |88, to be described hereinafter. The contact arm 19 of the safety pilot is connected through line 91 and line 88a to terminal 88 of the secondary of transformer 8| and to the flexible contact arm 46 of the controller. It is thus seen that when contact arm 19 is in engagement with contact C, a circuitis completed to heater 3|.

An igniter, such as a conventional hot wire igniter 82 suitably mounted to ignite the pilot burner, is adaptedvto be energized by a transformer 83. One terminal of the igniter transformer is connected through line 84 to terminal 3|b of the vcontroller and the other terminal is connected through line y85 to contact 1| through terminal 13. It is thus apparent that the igniter cannot be energized unless both the contact 19 is in engagement with contact C and contact arm 63 is in engagement with contact 1|.

A remote control panel v86 is adapted to be secured b v suitable means (not shown) to the wall of, or an object in a room remotely positioned from the burner apparatus. However, the panel may be positioned adjacent the burner apparatus if so desired. It comprises a manually operable doubletbrow switch. preferably of the toggle type, wherein a movable contact member 81 is adapted to be selectively moved to engagement with an on contact or an oil contact therein. The movable contact member 81 is connected through line 88, terminal 16 and lines 89 and 98a to the other end of the above mentioned break in the main burner circuit and the terminal 98 of the transformer 8|. The 01T contact is connected through line 9| to terminal 52h of the controller. The on contact is connected to the other terminal of the conventional signal means |88, preferably a light, through line 92 and to one contact 93 of a push button switch through line 93a. Another contact 94 of the push button is connected through line 95 to terminal 61 of the controller. A push button bridging member 96 f the push button switch is normally biased to its contact onen position by means of a spring not shown.A Due to the fact that the push button is in series alternately with the igniter and the heater 3|, depending upon the position of contact arm 63, the only time that the igniter or heater 3| can be energized is when the push button is manually held closed.

As it is often desirable to control the heating system manually, especially if there should be an electrical power failure that renders the above described control means inoperative, an

' additional control means is provided on the controller which enables the pilot valve to be opened manually.

The manual control means comprisesa lever |8| secured to rotatable shaft |82 which extends through the back of the housing, panel 26 and frame 21. The shaft has a manual actuating knob |83 secured to the outer end thereof'. A transversely extending arm |84 on the lever |8| is positioned below the arm 33 and to the left of arm 53. It is thus seen that selective turning of the knob |83 in one direction or the other will move one or the other of said arms 33 and 53 to the position it would take if it were actuated by its heater. To provide for the return of arm |84 to an intermediate and inoperative position, a fork shaped spring |85 has its closed end around a headed pin |86 with its legs straddling a T-shaped arm |81 extending laterally from the lever I8| and a. second headed pin |86a. At least one leg of the spring will always be in engagement with the second pin while the other leg may be flexed outwardly by the T-shaped arm to permit rotation of knob |83.

The operation of the rest of the control apparatus will be the sare as if the arms 33 and 53 were actuated by their heat motors, except when ignition of the pilot burner-'is being attempted when no electrical power is available. In this case the igniter 82 will not operate and it will be necessary to ignite the pilot by other suitable means, such as a, match or taper.

Operation The system is shown in its shut down condition, that is, when the manually operable contact member 81 of the snap switch is in its off position, the pilot valve is in its closed position,

- and the safety pilot is in its cold position.

To initiate operation of the heating system, as in the fall, the operator first moves the contact member 91 into engagement with the "on" contact. This completes a circuit from the terminal 98 of the transformer 8|, through part of line 98a, line 88, terminal 16, line 88, movable contact member 81, on contact, line 92, signal |88. line 98, part of line 99, contact C of the safety pilot, contact arm 19, part of line 81. and line 88a to the other terminal '88 of the transformer 8|. This energization of the signal |88 indicates to the operator that the pilot burner is not lighted and that the system requires ignition of the pilot burner to put it into operation. The operator then presses on the push button switch to bridgecontacts 93 and 94 to complete a circuit, in parallel with the signal |88, from line 92 through linev 93a contact 93, bridge 96, contact 94, line 95, termina1 |61, switch arm 63` contacts 65 and 68, connector 69a, heater 3|, connector 3|a, and terminal 3|b to line 98. Energization of heater 3| causes the bimetallic actuating arm 32 to move upwardly opening the pilot valve and closing contacts 44 and 46. Slight additional movement of the arm 32 after contact arm 45 engages contact 44, brings the abutment shoulder 33a on arm 33 into alignment with notch 54 in bimetallic arm 53, thus permitting compression spring 6| to move arm 53, insulation bar 14 and contact arm 63 out of engagement with contact 68 and into engagement with contact 1|.

Separation of contact 65 from 68 deenergizes heater 3| but the nonnal tendency of the bimetallic arm 32 to return to its valve closing position is checked by the lower portion of the notch 54 engaging under the shoulder 33a. With the push button still maintained in a closed position by the operator, a circuit in parallel with the signal |88 is now completed from line 92 through line 93a, contact 93, bridge 96, contact 94, terminal 61, contact arm 63, contacts 64 and 1I, terminal 13, line 85, igniter transformer 83,

`c ounterclockwise to lift the arm 33.

line 84, to line 99 through terminal 3|b. Although contact 44 is now in engagement with contact arm 45, the heater 52 remains deenergized due to the fact that contact member 81 is disengaged from the oiT contact of the manual switch. Upon ignition taking place at the pilot burner, the safety pilot will be actuated to move the contact arm 19 from contact C to contact H thus breaking the circuit to the igniter and the signal. Deenergization of the signal indicates to the operator that the pilot burner is lighted and the main burner system is in operation and that the gniter is deenergized.

The operator may then release the push button, which additionally breaks the circuit to the igniter so that, if for any reason the` pilot burner should gc out, and the contact arm 19 moves to its` cold position, automatic re-ignition will not take place. In this way, unsafe re-ignition of the pilot burner is prevented.

Upon the pilot burner accidentally going out, the signal |00 becomes energized indicating to the operator that re-ignition of the pilot burner is necessary. However, the operator, knowing that the system has recently been in operation, is able to take care that a safe ignition condition exists in the furnace before closing the circuit to the igniter by means of the push button.

When it is desirable to shut down the heating system, as in the spring, all that the operator has to do is to move the contact member 81 of the snap switch from its on position to its oi position. This completes a circuit from terminal 90 of the tranformer 8| through line 90a, line 89, terminal 16, line 88, contact arm 81, off contact, line 9|, terminal 52h, connector 52a, heater 52 connector 45a, contact 44, contact arm 46, terminal 48, line 91, and line 80a to the other terminal 80 of the transformer 8|. This causes energization of heater 52 which warps bimetallic arm 53 toward the right, causing contact 64 to leave contact 1| and contact 65 to engage contact 68. Upon the bottom portion of notch 54 moving out from under arm 33, such arm is released permitting tension spring 39 to lower bimetallic arm 32 to close the pilot valve and to permit contact arm 46 to separate from contact 44 thus breaking the circuit to the heater 52. Upon closing the pilot valve, cutting oi the ilow of gas to the pilot burner, the safety pilot will cease to be heated by the pilot burner, which will cause it to operate and move to its cold position with the contact arm 19 in engagement with contact C. The heating system has thus returned to its original shut down position as shown in the drawing.

In the event that it is desirable to start the heating system manually, as when there is no electrical power available, .this may be accomplished by rotating the manual control knob |03 This causes operation of the apparatus just as if the arm had been lifted by the heater 3|. The switch 81 must also 'be moved to on position to prevent power resumption shutting down the system.

Similarly, when it is desirable to turn oi the the system manually, it may be done by rotating the same manual control knob |03 clockwise to move the arm 53 outwardly to unlatch the valve control arm 33, permitting the valve I1 to close.

While I have described the preferred structure and operation of the invention, it is obvious that various modifications may be made therein without departing from the spirit of the invention. It is therefore to be understood that the scope of the invention is to be determined solely from the appended claims.

I claim as my invention:

1. A control mechanism, comprising, first and second electrically energized actuators each having a movable portion having energized and deenergized positions, said movable portions mechanically coacting with one another in such a manner that each when in its deenergized position holds the other in its energized position, and single manually operable means positioned between said actuators so that either one may be actuated thereby to its energized position.

2. A control mechanism, comprising, first and second electrically energized actuators each having a movable portion-having energized and deenergized positions, said movable portions mechanically coacting with one another in such a manner that each when in its deenergized position holds the other in its energized position, and manually operable crank means positioned between said actuators so that rotation in one direction will move one actuator to its energized position while rotation thereof in the opposite direction `will move the other actuator to its energized position.

3. Control apparatus comprising an igniter, a

fuel control means having a fuel-flow position and a no-ow position, a first electrical power means for actuating said control means to its fuel-flow position, holding means normally biased to a position wherein it mechanically retains said power means in said fuel-ilow position, a second electrical power means for actuating said holding means to a position wherein it releases the rst power means to return to the no-flow position of said control means and wherein it is mechanically retained in said position by said first power means, a normally open switch adapted to be actuated to a closed position upon movement of the ilrst power means to said fuel-flow position, said switch being in series with said second power means, and a single pole double throw switch having one contact connected to said ignitor and another contact in series with said first power means and adapted to be actuated by said second power means to open the circuit to said iirst power means and to simultaneously close the circuit to said igniter.

4. A control device comprising a fuel valve, a first bimetallic actuating arm for said fuel valve, said arm having a heater adjacent thereto and a notched member on one of its ends, a single pole double throw switch with one of its contacts in series with said heater and the other contact connected to a load terminal on said device, a second bimetallic arm for actuating said switch, said second arm having its longitudinal axis substantially at right angles to the longitudinal axis of said first arm and having a second heater adjacent thereto, said second arm also having a notch in an edge thereof spaced from one end thereof, said arms being so related to each other that each in its normal cooled position is adapted to hold the other in its heated position, and a second switch in series with said second heater and adapted to be actuated by said first arm.

5. A control device comprising a control means having a rst position and a second position, a rst power means for actuating said control means to its second position, holding means adapted to cooperate with said power means and normally biased to a position wherein it retains said control means in its second position, a second power means including said holding means for actuating said holding means to a position wherein it releases said first power means to permit it to move said control means to its first position and wherein it is retained in said position by said first power means, and a manually rockable lever adapted to selectively engage and actuate saidflrst or second power means, said lever being spring biased in each direction to normally hold it in an intermediate position between said first and second power means.

6. In a fuel control system, the combination comprising, a fuel control means, a first power means for moving said control means to a first Ifuel supplying position, a second power means -for holding said first power means in said fuel supplying position and movable to release said rst power means to return said control means to a second position wherein fuel flow is discontinued, connections including a first switch closable upon energization of said first power means to partially complete a power circuit to said second power means, an igniter, connections including a second single pole double throw switch selectively operable by said second power means to partially complete a circuit to said first power means when said second power means is in its energized position or to partially complete a circuit to said igniter when said first power means is in its energized position, connections including a third switch for selectively completing a circuit to either the movable contact of said second switch or to said second power means, a source of electrical power, and connections iricluding a fourth combustion responsive switch adapted to complete either a circuit from said source to main burner control means when fuel passing through said control means is burning or to partially complete a circuit from said source to said first power means when no fuel is burning.

'7. In a fuel control system, the combination comprising, a fuel control means, a first power means for moving said control means to a fuelflow position, a second power means for latching said rst power means in said position but movable when energized to permit the moving of said control means to a no-flow position, connections including a rst switch closable upon energization of said first power means to partially complete a power circuit to said second power means, an igniter, connections including a second single pole double throw switch for partially completing a power circuit to said first power means when said second power means is in its energized position or for completing a power circuit to said igniter when said first power means is in its energized position, connections including a third switch adapted to selectively complete a power circuit to either the movable contact of said second switch or to said second power means, a source of electrical power, connections including a fourth condition responsive switch for selectively completing either a circuit from said source of power to main burner control means when fuel is burning or a circuit from said source to said first power means when no fuel is burning, and connections including a fth biased-open switch in the circuit between said second switch and 10 said third switch adapted to be held closed only manually.

8. In a fuel control system, the combination comprising, a fuel control means, a first power means for moving said control mea-ns to a fueliiow position, a second power means positioned to hold said rst power means in said fuel-flow position but movable when energized to release said first power means to enable it to return said control means to a no-fiow position, connections including a rst switch which is closed by said first power means upon energization thereof to partially complete a power circuit to said second power means, an igniter, connections including a second single pole double throw switch adapted to selectively and partially complete a power circuit to said rst power means when said second power means is in its energized position or to said igniter when said first power means is in its energized position, connections including a third switch adapted to selectively complete a power circuit to either the movable contact of said second switch or to said second power means, a line between said second and third switches, a source of electrical power, connections including a fourth condition responsive switch for selectively completing either a circuit from said source to load terminals of said control system when fuel` is burning or a circuit from said source to said rst power means when no fuel is burning, a line between said fourth switch and said first power means, and connections including signal means mounted adjacent said third switch and connecting said line between said second and third switches to said line between said fourth switch and said first power means.

9. In a control system for a fuel burner, the combination comprising, connections including a single pole double throw switch having two pairs of contacts, an electrically operable fuel valve, a circuit including an igniterl electrically connected to said switch, a combustion responsive means .having a hot contact and a cold contact, said cold contact being electrically connected to said fuel valve and igniter, said hot contact being connectable to control means for said fuel burner and connections including a control switch for completing a power circuit to said fuel valve, said double throw switch being so arranged as to have one pair of its contacts normally closed and in series with said fuel valve but biased to .move when said fuel valve is opened to separate said one pair of contacts and thus break the circuit to said fuel valve and to complete the circuit to said igniter through the other pair of contacts on said double throw switch.

WALTER E. EDELMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,597,403 Cromie Aug. 24. 1926 1,687,366 Doolittle et al Oct. 9, 1928 1,825,611 Bangerter Sept. 29, 1931 2,135,829 McGoldrick Nov. 8, 1938 2,286,156 Petersen June 9, 1942 2,297,821 Whempner Oct. 6, 19'42 2,371,020 Beam Mar. 6, 1945 

